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Topic: What a drag (Read 566 times)

So upgraded the brake lines on the bike today to stainless steel Galfer's. When testing to make sure the rear brake worked alright I noticed it was dragging a lot (what a drag...). Took the caliper off the rotor and the wheel seemed to spin just fine, so figured it was something with the caliper not letting go. Fast forward a couple hours and my caliper is in all the pieces, rebuild kit is on it's way from Murph's, and there's brake fluid everywhere... so... much... brake fluid. Haha.... also my hands tingle, not sure if it's from the brake fluid or the brake cleaner... Probably spent a bit too much time letting the caustic chemicals sink in.

On a side note, when I was riding her a couple days ago, while waiting at a stop light she appeared to get a hot flash. Maybe it's just the hormone changes with a middle aged bike. But shortly after the fan came on, the thermometer jumped quite a bit. Not sure if it's just a faulty gauge or what, but figured someone might have some knowledge to lay on me. It was sitting at normal operating them and within about five seconds it rose a bunch. Any clue as to what it could be?

So upgraded the brake lines on the bike today to stainless steel Galfer's. When testing to make sure the rear brake worked alright I noticed it was dragging a lot (what a drag...). Took the caliper off the rotor and the wheel seemed to spin just fine, so figured it was something with the caliper not letting go. Fast forward a couple hours and my caliper is in all the pieces, rebuild kit is on it's way from Murph's, and there's brake fluid everywhere... so... much... brake fluid. Haha.... also my hands tingle, not sure if it's from the brake fluid or the brake cleaner... Probably spent a bit too much time letting the caustic chemicals sink in.

On a side note, when I was riding her a couple days ago, while waiting at a stop light she appeared to get a hot flash. Maybe it's just the hormone changes with a middle aged bike. But shortly after the fan came on, the thermometer jumped quite a bit. Not sure if it's just a faulty gauge or what, but figured someone might have some knowledge to lay on me. It was sitting at normal operating them and within about five seconds it rose a bunch. Any clue as to what it could be?

check your fans first, but an abnormal "jump" in thermo temps usually indicates either a looss connection, or the rivet on the sensor is loose, or actually a "low fluid/coolant" condition, where the coolant is trapped below the thermo, and when it opens, the temp is "sensed, and High...

aa good flush and fill, and burping (per a couple recent posts I made about "how to"), may be the cure...as for the brake rebuild, make sure to kinda 'hone' the piston exteriors, using some 200-400 grit wet/dry sandpaper, wetted with solvent, to create a light, clean "cross hatched sealing surface" kinda like a cylinder hone finish.. then, clean with brake cleaner before re assembly.. this makes the seals actually seal...Oh, don't goober brake fluid on stuff during re-assembly, especially on parts that will once installed, be exposed to atmosphere... it just sucks up moisture, and causes corrosion at an accelerated rate... put everything together dry and clean.

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30 YEARS OF KAW.....Rich R. (the other one..) COG 5977 JUSTAMEMBAHNOWand if you are gonna call me names... it's MR. Analdweeb if you please...

Wow, sure your not confusing your criteria for honing as it relates to something else. your the first person who recommends a 200 grit finish on the exterior of a piston that in many applications comes highly polished or chrome plated.I might use 4-600 grit to clean up minor corrosion in the caliper bore.Regardless, a 200 grit finish will not seal better than a polished piston against any of the squarecut or round synthetic caliper piston seals, it might even wear them out much quicker.

no, I do in fact understand "honing", and only used it for lack of a better term... maybe you should actually see what grit's the hones for various applications are really used, and which materials they are used upon.you may be surprised at just how coarse the media is, vs. the resultant finishes...

but,I will clarify, I did specify "lightly".

and, whatever you may think, having re-furbed many of these myself, along with fork tubes, what I said will not result in any problem/degradation/or seal issues...

if you have not done this, you are basing your response on something you assume, not something that has been seen to work fine by firsthand application.

shiny new mirror like chrome finish looks great, but in fact rubber seals of the nature used here, seal very well with an 8 to 16 Micro finish..which is much less than "mirror like".the chrome polished finish is more for corrosion resistance than seal, and the light 400 grit wet polish, does not cut thru the chrome, just gives it some "tooth" to allow the new seals to do what they do. It also provides what is considered a "torturous path" during the seal interface, preventing a "linear" path/leak"; the actual "grit" of the media (wet/dry sand paper, when wetted and used) is not a representation of the actual finish resultant from it's use, which is extremely less aggressive, and still "polished" as a result.

Mind you, I'm not saying to go hog wild, and ruin a piston... simply to clean them up, and remove any possible foreign contamination, pitting, or other such already degraded finish or annular/linear grooves that is/are present. It's all about the force applied, with the media, to result in an acceptable outcome.

if it makes you feel comfy, I'll revise my recommendation to say use 300 to 600 grit, wetted with solvent, but in essence, it may increase the effort to remove any "high spots" of corosive deposits present, and still result in the same after effect finish.

Its just a buffing thing.

« Last Edit: December 02, 2018, 11:44:32 pm by MAN OF BLUES »

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30 YEARS OF KAW.....Rich R. (the other one..) COG 5977 JUSTAMEMBAHNOWand if you are gonna call me names... it's MR. Analdweeb if you please...

The brake pistons are pushed out when the pads wear. So the sides of the pistons are subject to moisture, corrosion, and dirt. The honing MOB is suggesting is a way to clean and remove any corrosion or dirt embedded in the surface. It makes the diameter of the piston too large to move smoothly. If you do not remove this the piston will bind. I think this how this thread started (ie dragging brakes). A tiny bump of corrosion/rust can cut the new seals and cause a leak. The brake system uses the grip and flex of the seals to pull the piston away from the disc as the lever is released. Any binding of the piston will prevent this. Take care to clean the piston area anytime you push the pistons into the caliper even when changing tires.

So upgraded the brake lines on the bike today to stainless steel Galfer's. When testing to make sure the rear brake worked alright I noticed it was dragging a lot (what a drag...). Took the caliper off the rotor and the wheel seemed to spin just fine, so figured it was something with the caliper not letting go.

Not doubting the piston may have been hanging up but also inspect your saddlebag, the right bag tends to sag into the bike and has been known to press against the rear caliper. Just a something else to inspect while you are working there.

Alright, we can both agree abrading the piston surface to remove corrosion is an acceptable practice. I prefer scotchbrite and you use something else.I'm glad you revised your grit preference as I could see some DIY mechanic taking 150 or 200 grit paper he just finished sanding his kitchen cabinets with and going to town sanding his brake caliper pistons because he read it on this forum.

The brake pistons are pushed out when the pads wear. So the sides of the pistons are subject to moisture, corrosion, and dirt. The honing MOB is suggesting is a way to clean and remove any corrosion or dirt embedded in the surface. It makes the diameter of the piston too large to move smoothly. If you do not remove this the piston will bind. I think this how this thread started (ie dragging brakes). A tiny bump of corrosion/rust can cut the new seals and cause a leak. The brake system uses the grip and flex of the seals to pull the piston away from the disc as the lever is released. Any binding of the piston will prevent this. Take care to clean the piston area anytime you push the pistons into the caliper even when changing tires.

thanks,I always stress doing a cursory cleaning with a toothbrush, or stiff small bristle brush, and brake kleen, PRIOR to ever attempting to push pistons in, it makes a lot of sense, especially when the pistons have been sitting extended, and covered in 'contaminants" for a period of time, I just slide a caliper off, stick a piece of folded cardboard about the thickness of the disc in between the pads, and GENTLY press the lever to extend the pistons about 1/16" out further, then pull the pads, and scrub the pistons... making sure there is no "ridge" of grime and spooge.If all looks good then, I can feel safer about pressing the pistons in. If not, then I do an R/R on them...ScotchBrite pads, even the industrial gray ones, are really not highly abrasive, and MAY clean the piston somewhat, but it takes a lot more pressure...because it just tends to "round over" any lumps of stuff, and not really remove them... I still use a strip of sandpaper to clean them, as it cuts thru the high spots first, well before getting down to the actual surface of the rest of the piston...

the method I clearly stated, about using a specific wet/dry paper, wetted with solvent, should be understood.. so the"as I could see some DIY mechanic taking 150 or 200 grit paper he just finished sanding his kitchen cabinets with and going to town sanding his brake caliper pistons because he read it on this forum." ...thing/quote, is kinda out of that definition as "acceptable"... mechanical repairs do require some ability to comprehend and follow instruction... but I can see where you are coming from, having to repair many things people "fixed".

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30 YEARS OF KAW.....Rich R. (the other one..) COG 5977 JUSTAMEMBAHNOWand if you are gonna call me names... it's MR. Analdweeb if you please...

New kit is in the mail from Murph as we speak. Thanks for all the advice fellers!

As to the coolant stuff, I changed all the fluids, including coolant, a bout a month ago, when I got her. So she's definitely full and burped. Checked the levels and she's topped off. I'll definitely be poking around the connections. But just found it odd that the gauge would work normally up until that point and then climb so rapidly. On a related note, I have noticed that after running her for a while and putting her back in the stables, there is a notable "glug glug glug" sound of liquid. No leaks or anything, and figured it was probably fine, but might as well bring it up to see if it's a normal thing.

What I usta do on my c-10 when filling was to clamp a vice grip toward the bottom of the recovery to radiator hose and also fill that with coolant before replacing the rad cap, then remove the grip. It would seem to me that with the recovery tank mounted low like it is that the air trapped in that hose would be problematic for the cooling system.

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Yeah, if you want true ram air tuning, you better be willing to ram some air! (SiSF)Tick Tock, baby (Ironbuttal)Steve J Tavares, FL, one of the Floriduh Steves '15 Versys650LT, '98 KLR650, (back home), '99 C-10, 234k miles sold